The present study has been designed to investigate the effect of PSO supplementation on lipid profiles of hyperlipidemic subjects. The study has a randomized, double-blind and placebo-controlled design. Sixty-six hyperlipidemic subjects (serum cholesterol > 200 mg/dl and serum triglycerides > 150 mg/dl) are to be recruited from an endocrine clinic using a sequential clinical trial design and randomly assigned into groups, the PSO (n =33) and placebo (n =33) groups, for all of whom demographic data and medical history at baseline will be documented, and subjects will be given capsules containing either PSO or placebo for four weeks. The PSO group will consume PSO capsules, containing 400 mg PSO twice daily (800 mg PSO), while controls will take placebo capsules with the same dosage. Measurements of anthropometric indexes, body composition, blood pressure and physical activity, and 3 consecutive dietary recalls will be obtained at baseline and 4 weeks after supplementation. At baseline and after 4 weeks, medication and supplement use will be recorded in a questionnaire, and for biochemical measurements, after 12 to 14 hours overnight fasting, blood samples will be taken for biochemical analysis, including cholesterol, triglycerides, LDL-C, HDL-C, ox-LDL, insulin and of fasting plasma samples.